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            <h2 class="title" style="clear: both"><a id="mempset_clear_len"></a>DbMpoolFile::set_clear_len()</h2>
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      <pre class="programlisting">#include &lt;db_cxx.h&gt;

int DbMpoolFile::set_clear_len(u_int32_t len); </pre>
      <p>
         The <code class="methodname">DbMpoolFile::set_clear_len()</code> method sets the number of initial
         bytes in a page that should be set to nul when the page is created as
         a result of the 
         <a class="link" href="mempfget.html#mpoolfget_DB_MPOOL_CREATE">DB_MPOOL_CREATE</a> 
         or <a class="link" href="mempfget.html#mpoolfget_DB_MPOOL_NEW">DB_MPOOL_NEW</a>  
         flags specified to <a class="xref" href="mempfget.html" title="DbMpoolFile::get()">DbMpoolFile::get()</a>.  If no
         clear length is specified, the entire page is cleared when it is
         created.
    </p>
      <p>
         The <code class="methodname">DbMpoolFile::set_clear_len()</code> method configures a file in the
         cache, not only operations performed using the specified 
         <a class="link" href="memp.html" title="Chapter 9.  The DbMpoolFile Handle">DbMpoolFile</a>  handle.
    </p>
      <p>
         The <code class="methodname">DbMpoolFile::set_clear_len()</code> method may not be called after the
         <a class="xref" href="mempfopen.html" title="DbMpoolFile::open()">DbMpoolFile::open()</a> 
         method is called. If the file is already open in the cache when
         <a class="xref" href="mempfopen.html" title="DbMpoolFile::open()">DbMpoolFile::open()</a>  is
         called, the information specified to <code class="methodname">DbMpoolFile::set_clear_len()</code>
         must be consistent with the existing file or an error will be returned.
    </p>
      <p>
         The <code class="methodname">DbMpoolFile::set_clear_len()</code> <span>
            
            <span>
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.
            </span>
        </span>
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              <h3 class="title"><a id="idp9028464"></a>Parameters</h3>
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                <h4 class="title"><a id="idp9027816"></a>len</h4>
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          <p>
                          The <span class="bold"><strong>len</strong></span> parameter is the number of
                          initial bytes in a page that should be set to nul when the page is
                          created.  A value of 0 results in the entire page being set to nul
                          bytes.
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              <h3 class="title"><a id="idp9019904"></a>Class</h3>
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        <p>
                 <a class="link" href="env.html" title="Chapter 5.  The DbEnv Handle">DbEnv</a>, <a class="link" href="memp.html" title="Chapter 9.  The DbMpoolFile Handle">DbMpoolFile</a> 
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              <h3 class="title"><a id="idp9030424"></a>See Also</h3>
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                     <a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a> 
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